Quality Assurance and Quality Control in Radiography

Definition: An enclosed area, dimly lit by a safelight (usually red), where films are handled and processed.
Function: Protects film from white light and ionizing radiation during handling and processing.

Permanent Room: Include a floor area of at least 10 square meters.
Lightproof: Must exclude all external white light.
Conditions:
- Not damp or subject to temperature extremes.
- Equipped with water and electrical outlets.
- Should include sufficient space for dry and wet benches and a sink.
- Central to the x-ray examination area for efficiency.
- Well-ventilated with solid concrete walls (15 cm thick).
Special Features:
- Lead box inside for unexposed films.
- Walls/roof painted white or cream to reflect safelight.

Accessibility: Centrally located, serviced by hatches, and accessible to power/water.
Temperature Control: Ideal configuration away from damp/hot areas.

Critical Requirement: Must exclude all white light.
Sensitive Films: All films are sensitive to visible light; even small leaks can damage.
Lockable Door: Prevent accidental exposures and alert nearby workers of darkroom usage.

Prevention Measures:
- Ground all work surfaces/floor mats.
- Handle film properly and wear natural-fiber clothing (e.g., cotton).
- Maintain relative humidity at 30-60%.
- Clean screens regularly with antistatic cleaners.

Wall Shielding: Walls adjacent to the radiographic room should be shielded with suitable lead thickness (1.6 mm lead is mostly used).

Floor Characteristics:
- Non-porous, non-slip, chemical-resistant, durable, and stain-proof.
- Recommended materials: Asphalt, porcelain, or plastic tiles.
Walls:
- Light-colored to reflect light and easy to clean; should be covered with chemical-resistant materials.

Optimal Conditions: Maintain a comfortable working environment and ensure film handling/storage conditions are satisfactory.
- Relative humidity (30-60%) and temperature (18-24°C) should be regulated with at least 8-10 air changes/hour.
Ventilation System:
- Use of air-conditioning or extractor fans for adequate airflow.

White Lighting: Meant for inspection/maintenance purposes, should be of moderate intensity and centrally placed.
Safe Lighting:
- Direct Safe Lighting: Focuses directly on the work surface (e.g., beehive safelight).
- Indirect Safe Lighting: Reflects light off the ceiling; should be high enough to avoid direct shine on surfaces.

Composition: Gelatin dyed in appropriate color; impacts sensitivity based on the film type.
Replacements & Maintenance: Replace if degraded by heat; clean periodically.

Characteristics: Sensitive to green light; red/magenta added to the emulsion.

Testing: Use photo paper and coin method to ensure the safelight does not fog film.
Adjustment: Lower wattage or change elevation of the safelight if an issue is detected.

Function: Holds x-ray and intensifying screens; needs maintenance to avoid contamination and damage.
Handling: Use only manufacturer-recommended adhesives for screens.

Master Tanks: Maintain constant temperature for insert tanks holding developer and fixer.

Developer: Essential for converting latent images to manifest images; consists of various agents to facilitate the development process.
Fixer: Removes unexposed silver halide crystals and maintains the film's archival quality.

Conditions: Store chemicals in cool, dry areas; maintain proper film storage to prevent damage.
Radiographic Film Sizes: Common sizes include 14x17, 11x14, 10x12, etc.